Fireworks colors are a matter of chemistry. The colors come partly from the elements and compounds used in fireworks and partly by incandescence or light produced by different temperatures. Here’s a look at how fireworks colors work:
Firework Colors – Luminescence of Element and Compounds
When chemicals are heated, the ions emit characteristic wavelengths or colors of light. This works much like the flame test, a method used to identify a substance by its color in a flame. Metal ions are responsible for common colors:
|Red||strontium salts, lithium salts
lithium carbonate, Li2CO3 = red
strontium carbonate, SrCO3 = bright red
calcium chloride, CaCl2
calcium sulfate, CaSO4·xH2O, where x = 0,2,3,5
|Gold||incandescence of iron (with carbon), charcoal, or lampblack|
sodium nitrate, NaNO3
|Electric White||white-hot metal, such as magnesium or aluminum
barium oxide, BaO
|Green||barium compounds + chlorine producer
barium chloride, BaCl+ is bright green
|Blue||copper compounds + chlorine producer
copper acetoarsenite (Paris Green), Cu3As2O3Cu(C2H3O2)2 = blue
copper (I) chloride, CuCl = turquoise blue
|Purple||mixture of strontium (red) and copper (blue) compounds|
|Silver||burning aluminum, titanium, or magnesium powder or flakes|
Quality control is important in all aspects of fireworks design, including color formulation. Impurities and contaminants in the chemicals can completely ruin the effect. For example, even trace amounts of sodium in a chemical mixture will produce a bright yellow color that can drown out weaker colors.
Firework Colors – Incandescence
You know how a stove burner is dark when its relatively cool, red when its hot, and white-hot when you turn it all the way up? This is incandescence of the heating element, which is light emitted by the element as it gets hot. Fireworks also rely on incandescence for special effects and colors. Certain chemicals are red, orange, yellow, and white when heated. In particular, metals are heated to produce colored sparks, glitter, and fountain effects. Titanium, iron, and aluminum flakes are common metals heated to incandescence in fireworks.
Firework Periodic Table
Here’s a handy periodic table you can print that shows the principal elements used in fireworks. The table is color-coded, so you can see at a glance which colors are produced by heating certain elements.